x86: Remove create/destroy_irq()

No more users. Remove the cruft

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org
Link: http://lkml.kernel.org/r/20140507154336.760446122@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>